XBL 12 month card deal and family plan discount

Ok so Buy.com is running 12 month cards for Xbox live at $34.99 with free shipping (just have to opt out of the 3-5 day delivery when completing the transaction) at:

http://www.buy.com/prod/q/loc/101/223400383.html

Now here is the twist.  While talking to customer Service, if you are currently not a primary of a family plan, you can upgrade at no cost if you have 24 months of membership banked on your account.   So if you buy two of these 12 months at just shy of $70.00 then put them both on the same primary account, all you have to do is upgrade via your Xbox dashboard to the family plan and you will go from one account with 2 years to 4 accounts with one year under the family plan.

I have done this while on the phone with xbox live customer service and it worked.  So even though they say they never discount the family plan because you are already getting a deal at 4 tags for less then 2 you can get it even cheaper using this method. 

Unless somehow Microsoft set my account to do this behind the scenes I see this as saving you some cash.  If anyone tries this and works, I would love to hear from you to confirm what I said.

Cheers!